Description
Encode a fixed-width opaque key as a zero-based positional integer in an explicitly ordered unique UTF-16 alphabet; leading alphabet-zero symbols remain width evidence.
An opaque key’s representation can affect equality and ordering even when its underlying value is unchanged. Delimiter joining can be ambiguous, fixed-width padding can preserve numeric order within agreed bounds, and typed length-prefix framing keeps scalar types distinct. Lengths in this family count UTF-16 code units unless a different unit is stated.
Encode a fixed-width opaque key as a zero-based positional integer in an explicitly ordered unique UTF-16 alphabet; leading alphabet-zero symbols remain width evidence.
When to use this tool
Use this tool to encode a fixed-width opaque key as a zero-based positional integer in an explicitly ordered unique UTF-16 alphabet; leading alphabet-zero symbols remain width evidence.
How to use the tool and how it works
- Enter key, alphabet using the field definitions below.
- Run the operation. Correct input errors before interpreting an output.
- Read result.ordinal. Use the ordering, boundary rules and absence conditions described below.
Treat alphabet code units as ordered base digits, accumulate the key’s exact integer value, and return decimal text.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| key | One encoded or opaque key, interpreted under the operation’s exact convention. | Text, at most 8,192 UTF-16 code units; the operation’s grammar also applies. |
| alphabet | Ordered distinct UTF-16 code units used as allowed symbols or base digits. | Text, at most 8,192 UTF-16 code units; the operation’s grammar also applies. |
| Output field | Interpretation |
|---|---|
| result | Object containing the named fields below. |
| result.ordinal | Exact nonnegative base-alphabet ordinal as decimal text. |
{
"input": {
"key": "ba",
"alphabet": "abc"
},
"output": {
"result": {
"ordinal": "3"
}
}
}Limitations and assumptions
- Alphabet must contain at least two distinct UTF-16 code units; leading zero-symbols do not affect the ordinal.
- String framing and alphabet digits use UTF-16 code units, not bytes or grapheme clusters. Exact integer text accepts a signed decimal spelling of at most 256 digits before operation-specific range checks.
- Every declared top-level input field is required and unexpected fields are rejected. Ordinary strings are limited to 8,192 UTF-16 code units and lists to 128 entries, with tighter operation-specific bounds where stated. JSON text has bounded nesting and node counts.
- Numeric outputs must be finite and no larger in absolute magnitude than the safe-integer limit; operations returning exact large integers use decimal text. Positions are zero-based and spans end exclusively unless the operation explicitly states a different convention.
Alternative or Complementary methods
Use typed framing when distinct scalar types or tuple boundaries must remain distinguishable. Keep alphabet, width, normalization and numeric bounds consistent between producers and consumers.
References
Similar or alternative tools
- Opaque Key Fixed Alphabet Inverse
Decode an exact nonnegative ordinal into a caller fixed-width opaque alphabet key; rejects overflow rather than growing the key or truncating leading symbols.
- Opaque Key Alphabet Audit
Audit opaque key UTF-16 code units against an explicit caller alphabet with positions; not Unicode grapheme, entropy or checksum validation.